Robert Grosseteste and the Ordered Universe

Posted in History, The Universe and Stuff with tags , , on February 22, 2017 by telescoper

Tomorrow I’m off to the historic city of Lincoln to give a public lecture, the inaugural Robert Grosseteste Lecture on Astrophysics/Cosmology.

This new series of lectures is named in honour of Robert Grosseteste (c. 1175 – 9 October 1253), a former Bishop of Lincoln, who (among many other things) played a key role in the development of the Western scientific tradition. His De Luce seu de Inchoatione Formarum (“On Light or the Beginning of the Forms”), written around 1220, includes pioneering discussions about cosmogony, which contains many ideas that resonate what I shall be talking about in my lecture. In particular, De Luce explores the nature of matter and the cosmos. Seven centuries before the Big Bang theory, Grosseteste described the birth of the Universe in an explosion and the crystallisation of matter to form stars and planets in a set of nested spheres around Earth. It therefore probably represents the first attempt to describe the ordered system of the Heavens and Earth using a single set of physical laws.

Anyway, this led me to an interesting website about an interdisciplinary project that involves discussing Robert Grosseteste in the context of mediaeval science, called “Ordered Universe”. Here’s an interesting video from that site, which features both historians and scientists.

Cardiff, City of Cycling?

Posted in Bute Park with tags , , , , , , , on February 22, 2017 by telescoper

Two recent news items about Cardiff caught my attention so I thought I’d do a quick post. The first piece was about the terrible state of traffic congestion in the city. This doesn’t affect me directly as I normally work to work and back, but it has definitely got much worse in the last few years. The roads are regularly gridlocked, a situation made worse by the interminable and apparently pointless roadworks going on everywhere as well as absurdly slow and dysfunctional traffic lights. There’s a common view around these parts that this is being allowed to happen – or even engineered – so that Cardiff City Council can justify the introduction of congestion charging. This would be an unpopular move among motorists, but I think a congestion charge would not be a bad idea at all, as what the city really needs is to reduce the number of motor vehicles on its streets, to deal with the growing problem of pollution and long journey times.

One day, about six years ago,  I was almost run over three different times by three different vehicles. The first was near the car park in Sophia Gardens, where there are signs and road marking clearly indicating that there is a speed limit of 5 mph but where the normal speed of cars is probably more like 35; the guy who nearly killed me was doing about 60.

Next, in Bute Park, a heavy lorry belonging to the Council, engaged in some sort of “tree-management” business, thundered along the footpath past me. These paths used to be marked 5mph too, but the Council removed all the signs when it decided to build a huge road into the Park and encourage more vehicles to drive around inside. The lorry wasn’t going as fast as the Boy Racer of Sophia Gardens, but the size of the truck made it just as scary.

Finally, using a green light at the pedestrian crossing at Park Place I was narrowly missed by another car who had clearly jumped a red light to get onto the dual carriageway (Dumfries Place) leading to Newport Road.

I have to say things like this aren’t at all unusual, but that is the only time I’ve had three close encounters in one day! Although most car drivers behave responsibly, there seems to be a strong concentration of idiots in Cardiff whose antics are exacerbated by the hare-brained Highways Department of the local council. There are many things to enjoy about living in Cardiff, and the quality of life here is very good for a wide range of reasons, but of all the cities I’ve lived in it is by a long way the least friendly to pedestrians and cyclists.

Which brings me to the second news item, which is about Cardiff City Council’s ambitious new Cycling Strategy, which aims to double the number of trips made using cyclists over the next ten years. That still wouldn’t reach the level of Cambridge, where 30% of all journeys in the city are done by bicycle.

Cardiff has a long way to go to match Cambridge and further still to be like Copenhagen, one of the loveliest and most livable cities I’ve ever experienced, partly because of its traffic policies.

In the interest of balance I should also point out that I was once actually hit on a pedestrian crossing in Cardiff by a bicycle steered by a maniac who went through a red light. In this case, however, I did manage to push him off his bike as he tried to get away, so he ended up more seriously hurt than I was. I was hoping that a friendly car would run over his bike, which was lying in the road, but sadly that didn’t happen.

I hope in their desire to increase the number of cyclists, the town planners don’t forget those of us who travel on foot!

A night Out with Nigel Owens

Posted in LGBT, Rugby with tags , , , on February 21, 2017 by telescoper

I’ve had a busy morning teaching and a busy afternoon meeting some interesting people from IBM and elsewhere in connection with Data Innovation Institute business, so just time to mention that I’m looking forward tonight to an event at Cardiff Metropolitan University (whose campus is not far from my house) featuring renowned rugby referee Nigel Owens who, in case you hadn’t realized, is gay. The event is part of the celebrations in Cardiff of LGBT History Month.

I’ll update later with reflections on the evening, but in the meantime here’s some examples of him in action on the rugby field!

Update: it was a thoroughly absorbing evening. Nigel Owens spoke extremely engagingly (and without notes) about his upbringing in a small village  in rural Wales, his mental health struggles as he tried to come to terms with his sexuality, a (nearly successful) suicide attempt when he was in his twenties, and how his decision to come out publicly revitalised his career as an international referee. 

When he takes to the field on Saturday to officiate at the Six Nations match between Ireland and France, it will be his 75th international match as a referee, which is the most for any referee ever.

 

People are not “Bargaining Chips”

Posted in Politics with tags , , , on February 20, 2017 by telescoper

Today there has been a day of action under the banner of “One Day Without Us” to celebrate the contribution that migrants make to the United Kingdom and to the counter growing tide of racism and xenophobia associated with some elements of the recent campaign for this country to leave the European Union. Here’s a video produced by the campaign.

I wish to make it clear, as someone who was born in the United Kingdom, that I am appalled by the present government’s refusal to guarantee the rights of the millions of EU citizens who have made this country their home and enriched us all with their presence here. Migrants have had a positive effect over all sectors of the UK economy for a very long time, but I wish to highlight from my own experience the enormous contribution “migrants” – or as I prefer to call them “colleagues” – make to our Universities. Non-UK scientists form the backbone of the School of Physics & Astronomy here at Cardiff, just as they did in the School of Mathematical and Physical Sciences at the University of Sussex. Without them I don’t know how we’d carry on.

Now the Article 50 Bill has begun its progress through the House of Lords, I hope that it can be amended to force the government to stop treating such valuable people in such a despicable way. In the meantime all I can do – and I know it’s only a gesture – is say that the government does not speak for me, or for any of my colleagues, and that I hope and believe that it will be made to abandon its repellent notion that people can be treated like bargaining chips.

The Mower, by Philip Larkin

Posted in Poetry with tags , , , on February 20, 2017 by telescoper

The mower stalled, twice; kneeling, I found
A hedgehog jammed up against the blades,
Killed. It had been in the long grass.

I had seen it before, and even fed it, once.
Now I had mauled its unobtrusive world
Unmendably. Burial was no help:

Next morning I got up and it did not.
The first day after a death, the new absence
Is always the same; we should be careful

Of each other, we should be kind
While there is still time.

by Philip Larkin (1922-1985)

 

Not the Six Nations

Posted in Biographical, Rugby with tags , , , , on February 18, 2017 by telescoper

After a misty morning it has turned into a lovely Spring-like afternoon here in Cardiff. I’ve been in the School of Physics & Astronomy at Cardiff University this morning, helping out with a UCAS visit day by interviewing some prospective students and then having lunch and chatting with parents and others.

As well as the weather and the admissions season, another indication of the passage of the seasons is the Six Nations rugby. Our Saturday UCAS visit days have to be arranged with the RBS Six Nations fixture list in mind because Cardiff gets incredibly busy when Wales are playing at home. The capacity of the Millennium Principality Stadium is well over 80,000 which, for a City with a population of just over 300,000 represents a huge perturbation. 

Not only is there a lot of traffic and a very crowded city centre, but it’s also very difficult to find hotel accommodation at a reasonable price on match weekends.  Given that we start in the morning, quite a few prospective students and their families do stay overnight beforehand so this is quite an important consideration. There are no fixtures in the RBS Six Nations this weekend. Today two of my interviewees had travelled quite a long way to get to Cardiff – one from Richmond in North Yorkshire and another from Falmouth in Cornwall – and both families stayed over last night.

Anyway, while I’m not talking about the Six Nations I can’t resist mentioning last week’s match here in Cardiff between Wales and England. I didn’t have a ticket. I’ve ever really figured out how to get tickets for these matches. They always seem to be completely sold out as soon as they go on sale.

Before the match, I thought it was going to be a close game but Wales always have tremendous home advantage at Cardiff and I thought they might just sneak it. It was a rather dour struggle to be honest, but with less than ten minutes to go Wales were leading 16-14 and my suspicions seemed about to be confirmed. However, as is often the case with close matches, it was an error that produced the decisive moment.

About five metres out, Wales turned possession over and then rucked successfully, the ball eventually going to Jonathan Davies behind his own try line. With half of his team trying to disentangle themselves from the completed ruck, it was essential for him to clear his lines by kicking into touch. Unfortunately, he kicked straight down the field where his kick was collected by George Ford. England’s counter-attack was swift and lethal: Ford to Farrell and then to Elliott Daly on the wing, who went over for the try to the sound of groans all round Cardiff. After the conversion it was Wales 16 England 21, which is how the game ended a few minutes later.

The results of the other games so far mean that the only team capable of winning a grand slam is England, as each of the other teams has lost at least one game. There’s still a long way to go, however, and England still face challenging matches against Ireland and a much-improved Scotland.

Anyway, all this UCAS malarkey means that I’m way behind on Saturday crossword duties, so I’m going home. Toodle-pip.

Emergent gravity in galaxies and in the Solar System [GA]

Posted in The Universe and Stuff with tags , , on February 17, 2017 by telescoper

I’ve been meaning to do a blog post about Erik Verlinde’s  very interesting “Emergent Gravity” theory since it was first aired in November 2016, but never got round to it. However, this recent paper suggests that the new theory fails badly on scales of the Solar System. And when I say “badly”, I mean by seven orders of magnitude. That’s pretty bad.

Unless there’s something wrong with this analysis, this looks pretty terminal …

arXiver

http://arxiv.org/abs/1702.04358

It was recently proposed that the effects usually attributed to particle dark matter on galaxy scales are due to the displacement of dark energy by baryonic matter, a paradigm known as emergent gravity. This formalism leads to predictions similar to Modified Newtonian Dynamics (MOND) in spherical symmetry, but not quite identical. In particular, it leads to a well defined transition between the Newtonian and the modified gravitational regimes, a transition depending on both the Newtonian acceleration and its first derivative with respect to radius. Under the hypothesis of the applicability of this transition to aspherical systems, we investigate whether it can reproduce observed galaxy rotation curves. We conclude that the formula leads to marginally acceptable fits with strikingly low best-fit distances, low stellar mass-to-light ratios, and a low Hubble constant. In particular, some unobserved wiggles are produced in rotation curves because of the dependence of the transition on the…

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